1st time pulling head

[so]

hi all,

this is my first boat, motor is a 84 90 hp v4 evinrude. Took it out couple times and it ran pretty good. Did a warm compression test, numbers(from No.1 to No. 4) are: 130, 110, 130, 110.

I want to pull the head to just exam the cylinders, is it pretty much just unbolting the cylinder bolts, what are some do's and don'ts during the processing. what am I looking for? Do I need to replace the gasket and/or use gasket sealant when putting things back? Just bought a factory manual online and should be getting it soon.

thanks in advance.

 

[dreamchaser]

Re: 1st time pulling head

So, b4 u pull the heads try a decarb with seafoam , might help to clean engine up some ... shoot it thru the carbs while just off idle ..Myself i then shoot it thru the plug holes ....let it sit for a few hours or more ....After that if u want to pull the heads to look see, use "new " gaskets ,, not the old ones ....good luck ...

 

[mikesea]

Re: 1st time pulling head

look at the waterpassages that run around the block and head,be sure there is no salt or corrosion build up that may prevent proper cooling,look at the cyl walls for deep scratches,it may have fine criss cross lite scrath marks wich are supposed to be there,look at piston tops for any pitting,or corners that are broke off,the most important thing isa compression test which you did,are the 110 from one side and the 130 from the other side,it is a considerable differance,but if its the same side (130,110) then its possible that the head ,and or block could hve been resurfced ,thus making more sense.You want to chnge the head gaskets,as for sealer,there are alot of opinions,I say,and book says no sealer,but I had bosses that wanted sealer applied on the copper sealing ring,supposedly it prevents a alum.copper reaction????you want to be sure and torque the bolts down,starting in the middle first tighten snug,then going in increments tightening to 240 INCH pounds max.BUT,you want to be careful,The eveness is most important,if the threads look questionable,you might just go 220,seems they strip easier after that,again,a bosses opinion,that is what I did for him and had no problems.Be sure to chase the threads with a tap and be sure no dirt is in the bolt holes,this could through off your torque,bolts should be wire brushed and a coating of oil is recommended

 

[so]

Re: 1st time pulling head

thank you all for the info.

mikesea, can you explain what do you mean by "chase the threads with a tap"? thanks

Also, just to make sure, I should be removing the bigger-size bolts (sitting around the outter perimeter)that secure the head to the block, not the smaller ones forming the inner circle, correct? pls refer to attached picture.
thanks.

 

[DHPMARINE]

Re: 1st time pulling head

Pull the heads if you must.I would wait until the engine gives you a reason to.

Kind of almost fits under the heading "Fix it till it's broke"

DHP